Siemens SIMATIC S7-1200 - Page 79

Installation
4.4 Wiring guidelines
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
79
A summary of Wiring rules for the S7-1200 CPUs, SMs and SBs is shown below:
Table 4- 17 Wiring rules for S7-1200 CPUs, SMs, and SBs
Wiring rules for...
CPU and SM connector
SB connector
Connectible conductor
cross-sections for stand-
ard wires
2 mm
2
to 0.3 mm
2
(14 AWG to 22
AWG)
1.3 mm
2
to 0.3 mm
2
(16 AWG to 22
AWG)
Number of wires per con-
nection
1 or combination of 2 wires up to
2 mm
2
(total)
1 or combination of 2 wires up to 1.3
mm
2
(total)
Wire strip length
6.4 mm
6.3 to 7 mm
Tightening torque* (maxi-
mum)
0.56 N-m (5 inch-pounds) 0.33 N-m (3 inch-pounds)
Tool 2.5 to 3.0 mm flathead screw-
driver
2.0 to 2.5 mm flathead screwdriver
* To avoid damaging the connector, be careful that you do not over-tighten the screws.
Note
Ferrules or end sleeves on stranded conductors reduce the risk of stray strands causing
short ci
rcuits. Ferrules longer than the recommended strip length should include an
insulating collar to prevent shorts due to side movement of conductors. Cross
-sectional area
limits for bare conductors also apply to ferrules.
See also
Technical specifications (Page 1359)
Guidelines for lamp loads
Lamp loads are damaging to relay contacts because of the high turn-on surge current. This
surge current will nominally be 10 to 15 times the steady state current for a Tungsten lamp.
A replaceable interposing relay or surge limiter is recommended for lamp loads that will be
switched a large number of times during the lifetime of the application.